Laser Cutting

By: Annett Klotzbach

Fraunhofer IWS

Carbon fiber reinforced polymers (CFRP) are increasingly applied in the aircraft industry as well as the automobile industry. The main reason is the highly mechanical load on one hand and the low density on the other hand. Moreover, the corrosion resistance plus the damping behavior of the material can fully be utilized in highly stressed structures. However, the concept of manufacturing CFRP-parts near- net- shape does not substitute the need of cutting them. The different properties of fiber- and matrix-material constitute an ambitious challenge for the CFRP cutting process with a laser beam. Main influencing parameters are the different thermo-optical characteristics of fiber and matrix. The carbon fibers have a more than 20 times higher sublimation temperature than the decomposition temperature of the resin. Because of a good heat conduction of the fibers, the resin fitting at the fibers will quickly be decomposed, before the carbon fiber itself is cut (Fig.1). The theory to decrease the heat affected zone is to minimize the interaction time between laser radiation and material.

The benefit of the availability of high power and high brilliant laser sources enables ablation and/or cutting processes with high processing speeds. However, the relation between wavelength and absorption on non-isotropic materials on the one hand, the influence of the intensity and the processing speed on the other hand, require fundamental research.

Within the experiments a continuous-wave (cw)-single mode fiber laser was applied in comparison with a Q-switched pulsed laser system (50 W, 100 ns). Using the Remote technology (the laser beam will be deflected by two galvo – driven tilting mirrors) a minimized heat interaction time between material and laser beam can be reached. The setup of the cw-Remote processing is shown in Fig. 2.

The material to be processed was a 3 mm thick consolidated CFRP with epoxy resin. Its fiber volume percentage is about 50% with multidirectional orientation of the long fibers.

As a result two cross sections can be seen:

Fig.3

Cross section of CFRP using cw – laser & Remote processing

Pl = 3 kW, vaverage = 9 m/min, ET = 11 J/mm²

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig.4

Cross section of CFRP using Q-switched – laser & Remote processing

Pl = 50 W, vaverage = 0,04 m/min, ET = 28 J/mm²

 

 

 

 

 

 

 

 

 

 

 

 

The Remote technology proved to be an excellent tool to cut consolidated CFRP with good cut qualities. Average processing speeds of more than 10 m/min can be reached using high brilliant and high power cw – lasers. The heat affected zone can be minimized by decreasing the interaction time. One possible way is to use Q-switched lasers with short pulse lengths. However, because of the limited overall laser energy, the average processing speed is quite low.

Fig. 1: REM image of CFRP, gas assisted laser cutting

 

 

 

 

 

 

 

 

Fig. 2: Experimental setup for Remote processing

 

 

By: Xinghua Li and Sean Garner

Ultra-slim flexible glass substrates have many potential applications, spanning from photovoltaics to e-paper to touch sensors. Previously, these applications generally incorporated glass substrates in the thickness range of 0.3-1.0 mm and benefited from inherent glass properties including high optical transmission, low surface roughness, high thermal and dimensional stability, and low CTE. Recently, however, there is interest in reducing the thickness of the substrate to ≤200 mm. Glass substrates at this thickness still provide the inherent beneficial properties of glass, but they also enable substrate flexibility and end product devices that are thinner and lighter weight. [click to continue…]

A Technical and Commercial Comparison of Fiber Laser and CO2 Laser Cutting

September 22, 2013

By John Powell, Alexander Kaplan Since the advent of commercial fiber and disk laser cutting machines, there has been a lot of controversy about the performance of these devices – particularly in comparison to their more established CO2 counterparts. In the early days, the sales staff promoting fiber technology would often declare that the new […]

Read the full article →

A Study on Laser Cutting of Textiles

March 4, 2011

By: Dr. Nukman bin Yusoff Laser cutting technology is a non-conventional machining which being used widely in many industries. However, the application of this technology in textile industry is still new and yet to be explored. Indeed, nowadays many textile industries are preferred to cut the textile by using conventional way such as discs, band […]

Read the full article →

Fiber Laser Blanking of Coil Strips at Extreme-Speed Extreme-Power

February 17, 2011

By: Dr. Charles Caristan and Jay Finn Air Liquide Industrial US LP, Automatic Feed Company The blanking process consisting of cutting flat panels directly out of a metal coil is practiced in the automotive industry to the tune of 10 MM tons of steel coils processed each year for the North American market alone.  Up […]

Read the full article →

Leading Technology for the Customer’s Benefit – Laser Processing Heads for Welding and Cutting

February 17, 2011

By: Dr. Markus Kogel-Hollacher For decades Precitec has been the leading manufacturer of processing heads suitable for all laser sources including fiber lasers, disc lasers, CO2 lasers, diode lasers, Nd:YAG lasers from powers ranging from the typically used power spectrum up to 30 kW. These are directly applicable to industrial laser materials processing in order […]

Read the full article →